Mineral oil composition containing an improved hydrocarbon-phosphorus sulfide reaction product



MINERAL GEL COMPGSHEGN ONTA1NING AN IMPRQVED HYDRGCARBGN-PHGSPHORUS SUL- FEDE REACTION PRODUCT Max W. Hill, Somerville, N. 3., and Robert H. Jones,

Irvington, N. Y., assignors to Essa Research and Engineering Company, a corporation of Delaware No Drawing. Application November 1, 1951, Serial No. 254,441

Claims. (ill. 252-466) This invention relates to mineral oil compositions and particularly to lubricants containing a detergent additive. This application is a continuation-in-part of copending application Serial No. 129,196, filed November 23, 1949, now U. S. Patent 2,640,053, issued May 26, 1953. I

The art of metallic detergents for lubricating oil compositions adapted for use in internal combustion engines is well known to those versed in this field and has resulted in substantial improvements in lubricants. These detergents are particularly useful in lubricating oil compositions which are employed in internal combustion engines used in the operation of automobiles, aircraft and similar vehicles, including diesel en to improve their operation by preventing or retarding corrosion, piston ring sticking, cylinder wear, and carbon and varnish formation. However, when metallic detergents are used in lubricating c npositions where oil coisumption is high and engine conditions are severe, such as in aircraft engines or where such concentrations of metallic detergents are used to maintain engine cleanliness under conditions where high deposit fuels of cracked or high sulfur nature are used, such as in automobile and diesel operation, the ash content from the metallic detergent accumulates in the combustion chamber and causes pre-ignition, detonation, spark plug fouling, valve burning, and ultimate destruction of the engine.

it is known that the acidic product obtained by reacting a sulfide of phosphorus with a hydrocarbon possesses mild detergent properties when incorporated in a mineral lubricating oil. However, this product is objectionable for commercial use in the fact that it gradually evolves hydrogen sulfide and accordingly gives forth a very disagreeable odor. Furthermore, such products are unstable and on standing for a short time at room temperature tend to precipitate a light colored solid material.

It has been found, in accordance with the present invention, that if this reaction product of phosphorus sulfide and a hydrocarbon or essentially hydrocarbon material is contacted with a hydrocarbon having one or more olefinic double-bonds, a reaction takes place with the evolution of heat, even at ordinary temperatures; and the product of this reaction is not only very satisfactory from the standpoint of detergency and corrosion inhibiting properties when incorporated in lubricating oils and other mineral oil products, but also is more stable with respect to hydrogen sulfide evolution and precipitation of solids on standin for long periods of time. Furthermore, because the product contains no metal, it is free from the objectionable feature of leaving a metallic deposit or ash when used as an additive for the crankcase lubricant of an internal combustion engine. These compounds are also effective, not only when added directly to the crankcase lubricant, but also when added to the engine fuel, since in the operation of the engine it will work its way from the combustion chamber into the crankcase and there blend with the lubricant.

The additives of the present invention are also useful Patented July s, was

p nile in extreme pressure gear oils, greases and the like to enhance their load carrying capacity where unit loads are exceptionally high as, for example, in automotive differential units and hypoid gearingv In the first step of the preparation of the additives employed in accordance with the present invention a sulfide of phosphorus is reacted with a hydrocarbon material to form a phospho-sulfurized hydrocarbon. The sulfide of phosphorus which can be employed includes P253, P255, P452, P457 or other phosphorus sulfide, and is preferably phosphorus pentasulfide (P285). Mixtures of two or more phosphorus sulfides may also be employed as well as mixtures of elemental phosphorus and sulfur.

' The hydrocarbon materials which may be reacted with a phosphorus sulfide may be paraflins, olefins or olefin polymers, diolefins, acetylenes, aromatics or alkyl aro matics cyclic aliphatics, petroleum fractions, such as lubricating oil fractions, petrolatums, waxes, cracked cycle stocks, or condensation products of petroleum fractions, solvent extracts of petroleum fractions, etc. Normally liquid hydrocarbons are usually preferred. Particularly preferred materials are mineral lubricating oil base stocks.

Hydrocarbons such as bright stock residuums, lubricating oil distillates, petrolatums or paraffin waxes may be employed. There may also be employed products obtained by condensing any of the foregoing hydrocarbons, usually through first halogenating the hydrocarbon, with aromatic hydrocarbons in the presence of anhydrous inorganic halides, such as aluminum chloride, zinc chloride, boron fluoride, and the like.

As examples of monoolefins may be mentioned isobutylene, decene, dodecene, cetene (C16), octadecene (C18), cerotene (C26), melene (C30), olefinic extracts from gasoline or gasoline itself, cracked cycle stocks and polymers thereof, resin oils from crude oil, hydrocarbon coal resins, cracked waxes, dehydrohalogenated chlorinated Waxes, and any mixed high molecular weight alkenes obtained by cracking petroleum oils. A preferred class of olefins are those having at least 20 carbon atoms per molecule, of which from about 12 to about 18 carbon atoms, and preferably at least 15 carbon atoms, are in a long chain. Such olefins may be obtained by the dehydrogenation of paraffin waxes, by the dehydrohalogenation of long chain alkyl halides, by the synthesis of hydrocarbons from C0 and H2, by the dehydration of alcohols, etc.

Another class of suitable olefinic materials are the monoolefin polymers, in which the molecular weight ranges from to 50,000, preferably from about 250 to about 10,000. These polymers may be obtained by the polymerization of low molecular weight monoolefinic hydrocarbons, such as ethylene, propylene, butylene, isobutylenefnormal and isoamylenes, or hexenes, or by the copolymerization of any combination of the above monoolefinic materials.

Diolefins which may be employed include well known materials such as butadiene, isoprene, chloroprene, cyclopentadiene, 2,3-dimethylbutadiene, pentadiene-1,3, hex-'- copolymerization of a low molecular weight olefin and a non-aromatic hydrocarbon showing the general formula CnH21t I, in which x is 2 or a multiple of 2, in the presence of a catalyst of the Friedel-Crafts or peroxide type. The low molecular weight olefin is preferably an isoolefin or a tertiary base olefin preferably one having less than 7 carbon atoms per molecule. Examples of such olefins are isobutylene, Z-rnethylbutene-l. Z-ethylbutene-l, secondary and tertiary base amylene, hexylenes, and the like. Examples of the non-aromatic hydrocarbons of the above formula which can be used are the conjugated diolefins listed in the preceding paragraph, diolefins such as 1,4-hexadiene, in which the double bond is not conjugated, as well as the acetylenes. The copolymerization is preferably carried out in the presence of aluminum chloride, boron fluoride, or benzoyl peroxide. and the copolymer is preferably one having a molecular Weight of about 1,000 to 30,000.

Another class of hydrocarbons which may be employed in a similar manner are aromatic hydrocarbons, such as benzene, naphthalene, anthracene, toluene. xylene. diphenyl, and the like, as well as aromatic hydrocarbons having alkyl substituents and aliphatic hydrocarbons having aryl substituents.

A still further class of hydrocarbons which may be employed in the reaction with sulfides of phosphorus are condensation products of halogenated aliphatic hydrocarbons with an aromatic compound, produced by condensation in the presence of aluminum chloride or other Friedel-Crafts type catalyst. The halogenated aliphatic hydrocarbon is preferably a halogenated long chain paraffin hydrocarbon having more than 8 carbon atoms, such as parafiin wax, petrolatum, ozocerite wax, etc. High viscosity paraffin oils, particularly heavy residual oil which has been treated with chemicals or extracted with propane or other solvents for the removal of asphalts, may be employed. The aromatic constituent may be naphthalene, fiuorene, phenanthrene, anthracene, coal tar residues, and the like.

Another type of hydrocarbon material which may be similarly employed is a resin-like oil which has a molecular weight of from about 1,000 to 2,000 or higher, obtained preferably from a paratfinic oil which has been dewaxed and which is then treated with a liquified normally gaseous hydrocarbon, e. g., propane, to precipitate a heavy propane-insoluble fraction. The latter is a substantially Wax-free and asphalt-free product having a Saybolt viscosity at 210 F. of about 1,000 to about 4,000 seconds or more.

The phosphorus sulfide-hydrocarbon reaction product may be readily obtained by reacting the phosphorus sulfide with the hydrocarbon at a temperature of about 200 F. to about 600 F., and preferably from about 300 F. to about 550 F., using from about one to about ten, preferably about two to about five molecular proportions of hydrocarbon to one molecular proportion of the sulfide of phosphorus in the reaction. It is advantageous to maintain a non-oxidizing atmosphere, such as an atmosphere of nitrogen, above the reaction mixture. Usually it is desirable to use an amount of the phosphorus sulfide that will completely react with the hydrocarbon so that no further purification becomes necessary. In the case of monoolefin polymers the preferred ratio is one molecular proportion of the sulfide of phosphorus to two to five molecular proportions of polymer. in such case the reaction is continued until all or substantially all of the phosphorus sulfide has reacted. The reaction time is not critical, and the time required to cause the maximum amount of phosphorus sulfide to react will vary with the temperature. A reaction time of two to ten hours or more is frequently necessary.

It is generally desired to carry out the treatment under conditions such that the treated hydrocarbon has a phosphorus content above about 2% and a sulfur content above about by weight. Phosphorus and sulfur contents as high as 5% and 12% or higher, respectively may be achieved providing the material does not become insoluble in the oil base stock in which it is used. If desired, the reaction product may be further treated by blowing with steam, alcohol, ammonia, or an amine at an elevated Til temperature of the range of about 200 F. to about 600 F. to improve the odor thereof.

The product obtained by reacting a sulfide of phosphorus with a hydrocarbon material in accordance with the process described above is then further reacted with an unsaturated hydrocarbon by contacting the two materials at room temperature, if desire-d, or more preferably at a somewhat elevated temperature, generally for times ranging from about A to hours. Temperatures ranging from about 60 to 400 F., using from about 0.1% to 50%, preferably about 5% to 20%, by weight of the unsaturated hydrocarbon, based on the amount of phosphorus sulfide-hydrocarbon product present, will generally be used.

The reaction is continued for a period of about one to about ten hours. The unreacted olefin is removed from the final product by distillation. However, in certain instances it may be desirable to employ an excess of the olefinic material or other unsaturated hydrocarbon products, thereafter adding a sufficient quantity of sulfur to form a still more effective addition agent. This last step may also be made more efiective by the addition of an agent commonly used in the vulcanization of rubber, such as Tuads, Captax, Tellurac, Selenac, or guanidine or substituted guanidines.

The unsaturated hydrocarbon material which is reacted With the phosphorus sulfide-hydrocarbon product in accordance with the present invention may be any aliphatic, cycloaliphatic, terpenic, or aliphatic-aromatic hydrocarbon containing at least one double bond carbonto-carbon linkage in a non-aromatic group. The materials are preferably non-acetylenic in nature and include the olefins, e. g., propylenes, butylenes, diisobutylenes, triisobutylenes, the codimer of isobutylene and n-butylene, also cracked gasoline fractions, cracked parafiin wax, viscous olefin polymers such as medium or high molecular weight polybutene, cyclopentene, cyclohexene, butadiene, pentadiene, isoprene, dipentene, a-pinene, fi-pinene, terpinolene, A-2,4(8)-p-menthadiene, styrene, and other aliphatic, cycloaliphatic and terpenic mono-olefins and diolefins. Derivatives of the above described compounds containing various non-reactive substituent groups and atoms may be used to advantage, since such groups or atoms would not interfere with the reaction. Such substituted groups and atoms include nitro groups, halogen atoms, etc. Hydrocarbon materials containing from 2 to carbon atoms per molecule may generally be employed.

Since the additives of the present invention are to be dissolved in mineral oils, the hydrocarbons which are reacted with a sulfide of phosphorus, and the materials which are further reacted with the products thus formed will be chosen with a view to provide a product which is soluble in the oil base or which has such marginal 1 solubility that it can be plasticized with high molecular weight alcohol, ester, or other plasticizer.

When additives of the present invention are employed in mineral lubricating oils, they are preferably added in proportions of about 0.001 to as high as 20%. Preferably 1.0 to about 6.0% may be used as a detergent whereas for automotive hypoid gears, a concentration of 5 to 20%, preferably about 8 to 12%, will generally be used. The proportions giving the best results will vary somewhat according to the nature of the additive and the specific purpose which the lubricant is to serve in a given case. For commercial purposes, it is convenient to prepare concentrated oil solutions in which the amount of additive in the composition ranges from about 20% to by weight, and to transport and store them in such form. In preparing a lubricating oil composition for use as a crankcase lubricant the additive concentrate is merely blended with the base oil in the required amount.

In certain cases it may be found that the effect of adding compounds of the type described above to a lubricating oil will be to increase the detergent effect of the oil without sufiiciently providing oxidation resisting characteristics. In such a case it is advantageous to add to the lubricant, in addition to the additives of the present invention, a substance containing sulfur and/ or phosphorus. Elemental sulfur may be used for this purpose or an organic sulfur compound, particularly an organic sulfur compound capable of being decomposed to give free sulfur at a temperature to which the lubricant is subjected during use. Examples of such organic sulfur compounds are sulfurized mineral oils, terpenes, olefins, and diolefins, sulfurized animal and vegetable oils, sulfurized isobutylene polymer, etc.

Below are given detailed descriptions of preparations of examples of lubricating oil additives described above as well as engine tests in which an oil containing the additives was used as the lubricant. It is to be understood that these examples are given as illustrations of the present invention and are not to be construed as limiting the scope thereof in any way.

Example 1 42.4 lbs. of a lubricating oil bright stock of 150 seconds viscosity (Saybolt) at 210 F. was treated with g. of benzoyl peroxide and 4.25 lbs. of P235. The mixture was stirred under an atmosphere of nitrogen gas at 350-370 F. for 3 hours and filtered. 250 g. of the product thus obtained and g. of diisobutylene were vigorously stirred and heated for two hours at 240-260 F. Nitrogen gas was bubbled through the reaction mixture and the temperature was raised to about 400 F. over a two hour period and the finished additive obtained by filtration.

Example 2 A product was obtained using the same reaction conditions and the same materials as in Example 1, except that commercial dipentene was used instead of diisobutylene in the second step of the process.

Example 3 A product was prepared by reacting a portion of the bright stock of Example 1 with about 17 weight percent of P285, based on the oil, in a nitrogen atmosphere for 10 hours at a temperature within the range of 400 to 425 F. After filtration, the product was treated with 20 weight percent, based on the product, of commercial dipentene for 1.0 hour at 380 F. temperature. The resulting product contained about 3.3 weight percent phosphorus and about 6.7 weight percent sulfur.

Example 4.-Laus0n engine test The products prepared by the methods of Examples 1 and 2 and a sample of the untreated PzSs-bright stock reaction product were blended in 4% concentration in a lubricating oil base consisting of a solvent extracted Coastal naphthenic oil of seconds (Saybolt) viscosity at 210 F. The blends were submitted to a standard Lauson engine test, which was conducted by operating the Lauson engine at 1800 R. P. M. for 20 hours with a 1.5 indicated kilowatt load, 300 F. oil temperature and 295 F. water jacket temperature. A similar test was applied to the unblended base oil. The oils were rated by the demerit system, wherein an oil which produces a perfectly clean piston surface is giving a rating of zero, while a rating of 10 is given to an oil which produces the worst condition which could be expected on that surface. The loss in weight of the copper-lead bearing was 6 also determined. The results are shown in the following table:

Example 5.Gear oil tests S. A. E. gear lubricants were formulated by blending 10 weight percent based on the finished oil, of the product of Example 3 with an oil base containing a refined Mid-Continent residuum and a Mid-Continent acidtreated distillate oil. The blend was submitted to a full scale test in accordance with U. S. Ordnance Specification MILL-2105. While the base oil per se does not meet the rigid requirements of this specification, the blended oil was satisfactory in most respects from such standpoints as High Speed-Low Torque Axle Test, CRCL1 9, High T c-rque-Low Speed Axle Test, CRCL20, storage stability, oil compatibility, foaming characteristics, corrosion resistance and rust protection.

T he products of the present invention may be employed not only in ordinary hydrocarbon lubricating oils but also in the heavy duty type of lubricating oils which have been compounded with such detergent type additives as metal soaps, metal petroleum sulfonates, metal phenates, metal alcoholates, metal alkyl phenol sulfides, metal organo phosphates, phosphites, thiophosphates, and thiophosphites, metal xanthates and thioxanthates, metal thiocarbamates, and the like. Other types of additives, such as phenols and phenol sulfides, may also be present.

The lubricating oil base stock used in the composition of this invention may be straight mineral lubricating oils or distillates derived from paraitinic, naphthenic, asphaltic or mixed base crudes, or, if desired, various blended oils may be employed as well as residuals, particularly those from which asphaltic constituents have been carefully removed. The oils may be refined by conventional methods using acid, alkali and/or clay or other agents such as aluminum chloride, or they may be extracted oils produced by solvent extraction wtih sol vents such as phenol, sulfur dioxide, etc. ydrogenated oils or white oils may be employed as well as synthetic oils prepared, for example, by the polymerization of olefins or by the reaction of oxides of carbon with hydrogen or by the hydrogenation of coal or its products. In certain instances cracking coil tar fractions and coal tar or shale oil distillates may also be used. Also, for special applications, animal, vegetable or fish oils or their hydrogenated or voltolized products may be employed in admixtures with mineral oils.

For the best results the base stocl; chosen should normally be an oil which without the new additive present gives the optimum performance in the service contemplated. However, since one advantage of the additives is that their use also makes feasible the employment of less satisfactory mineral oils, no strict rule can be laid down for the choice of the base stock. The additives are normally sufificiently soluble in the base stock, but in some cases auxiliary solvent agents may be used. The lubricating oils will usually range from about 40 to 150 seconds (Saybolt) viscosity at 210 F. The viscosity index may range from 0 to or even higher.

Other agents than those which have been mentioned may be present in the oil composition, such as pour point depressants, sludge dispersers, antioxidants, thickeners, viscosity index improvers, oiliness agents, fatty oils, sulfurized fatty oils, resins, rubber, olefin polymers, and the like.

Assisting agents which are particularly desirable as plasticizers and defoamers are the higher alcohols having preferably 820 carbon atoms, e, g. octyl alcohol, lauryl alcohol, stearyl alcohol, and the like.

In addition to being employed in lubricants. the additives of the present invention may also be used in other mineral oil products such as motor fuels, hydraulic fluids, torque converter fluids, cutting oils. flushing oils, turbine oils, transformer oils, industrial oils, process oils, and the like, and generally as antioxidants in mineral oil products. They may also be used in gear lubricants. greases and other products containing mineral oils as ingredients.

Since the reaction products of the present invention are powerful surface acting agents, they have practical use in dry cleaning fluids, in mineral spirit and aqueous paints. as flotation agents, as dispersants for insecticides in aqueous and non-aqueous solutions. and as additives for natural and synthetic rubber, as carbon black dispersant; and as vulcanization accelerators. The products of this invention may also be used as metal dispersants and antioxidants in colloidal iron electromagnetic clutches. They are useful dispersants in printing ink, asphalts, linoleum, roofing compositions, drilling muds, metal cleaners and pickling solutions, and as general commercial dispersant aids.

What is claimed is:

l. A mineral oil containing in the range of about 0.001 to 20% of a product obtained by reacting about 1 molecular proportion of a phosphorus sulfide with 2 to 5 molecular proportions of a hydrocarbon material and further reacting the acidic product thus formed with 0.1% to 50% of its weight of a hydrocarbon containing at least one olefinic double bond.

2. A composition according to claim l in which the mineral oil is a lubricating oil fraction.

3. A composition according to claim 2 in which the sulfide of phosphorus is phosphorus pentasulfide.

4. A composition according to claim 2 in which the phosphorus sulfide is phosphorus pentasulfide and in which the hydrocarbon product reacted with the same is a lubricating oil bright stock.

5. A mineral lubricating oil containing 0.001 to of a product obtained by reacting one molecular proportion of phosphorus pentasulfide with 2 to 5 molecular proportions of a lubricating oil bright stock and further reacting the product thus formed with 0.1 to 50% of its weight of diisobutylene.

6. A mineral lubricating oil containing dissolved therein 0.001 to 20% of a product obtained by reacting one molecular proportion of phosphorus pentasulfide with 2 to 5 molecular proportions of a lubricating oil bright stock and further reacting the product thus obtained with 0.1 to 50% of its weight of a terpene.

7. A mineral lubricating oil containing 0.001 to 20% of a product obtained by reacting phosphorus pentasulfide with ten times its weight of a lubricating oil base stock and further reacting the product thus obtained with one-tenth its weight of diisobutylene.

8. A mineral lubricating oil containing a detergent product obtained by reacting phosphorus pentasulfide with ten times its Weight of a lubricating oil bright stock and further reacting the product thus obtained with onetenth its weight of a terpene, said detergent product being present in a quantity sufiicient to maintain high engine cleanliness.

9. A composition consisting essentially of a mineral lubricating oil and the product as defined in claim 1, the amount of said product in the composition being 20 to by weight.

10. A composition consisting essentially of a mineral lubricating oil and the product as defined in claim 7. the amount of said product in the composition being 20 to 50% by weight.

11. A composition consisting essentially of a mineral lubricating oil and the product as defined in claim 8, the amount of said product in the composition being 20 to 50% by weight.

12. A mineral oil containing from 0.001 to 20% by weight of a product obtained by reacting a normally liquid hydrocarbon with a sulfide of phosphorus at a temperature above about 200 F. whereby a phosphosulfurized hydrocarbon containing a minimum of about 2% phosphorus and of about 5% sulfur is formed and further reacting said phospho-sulfurized hydrocarbon with from about 5 to 20% of its weight of an olefinic hydrocarbon containing at least one olefinic double bond at a temperature in the range of about to 400 F.

13. A composition according to claim 12, in which said normally liquid hydrocarbon is a mineral lubricating oil base stock.

14. A composition according to claim 12 in which said olefinic hydrocarbon is selected from the group consisting of aliphatic, cycloaliphatic and terpenic monoolefins and diolefins.

15. A mineral oil containing from about 1 to 15% by weight of a product obtained by reacting from 1 to 10 molecular proportions of a mineral lubricating oil base stock with one molecular proportion of phosphorus pentasulfide at a temperature in the range of 200 to 600 F. for at least two hours and further reacting the resulting phospho-sulfurized hydrocarbon with from 0.1 to 50% of its weight of an olefinic hydrocarbon at a temperature in the range of about 60 to 400 F. for about A to 20 hours.

References Cited in the file of this patent UNiTED STATES PATENTS 2,315,529 Kelso Apr. 6, 1943 2,528,732 Augustine Nov. 7, 1950 2,561,773 Augustine July 24, 1951 2,640,053 Hill May 26, 1953 

1. A MINERAL OIL CONTAINING IN THE RANGE OF ABOUT 0.001 TO 20% OF A PRODUCT OBTAINED BY REACTING ABOUT 1 MOLECULAR PROPORTION OF A PHOSPHORUS SULFIDE WITH 2 TO 5 MOLECULAR PROPORTIONS OF A HYDROCARBON MATERIAL AND FURTHER REACTING THE ACIDIC PRODUCT THUS FORMED WITH 0.1% TO 50% OF ITS WEIGHT OF A HYDROCARBON CONTAINING AT LEAST ONE OLEFINIC DOUBLE BOND. 